This invention relates to directional drilling systems. These systems are primarily applicable to horizontal directional drilling, and more specifically to earth and rock formation boring. Low pressure, high volume fluid conduits within the boring bit body are provided for the purpose of lubricating the bit and suspending spoils.
The system of the present invention is designed for lateral or horizontal directional drilling, where it is necessary to bore or drill through an earth-bound formation, such as rock, and still remain directable. This industry, sometimes called "trenchless digging," installs utilities around immovable objects, such as roadways, rivers and/or lakes, etc. As shown in FIG. 1, the conventional boring technique traditionally operates from a boring device or machine 10 that pushes and/or rotates a drill string 12 consisting of a series of connected drill pipes with a directable drill bit 14 to achieve an underground path or direction through which a conduit or utility device can be installed. A sonde 16 immediately follows drill bit 14 as it is directed over or under pipes 18. Sonde 16 transmits electronic positioning signals to worker 20 by way of a complementary receiving device 22.
As shown in FIG. 2, traditional methods of drilling include a drill body 30 and a drill blade 32 of some type that is usually concentric in design and creates a cylindrical hole about the same diameter as drill blade 32. The prior art methods and devices typically use high pressure high velocity jetting to create steerability and cooling of drill body 30 and blade 32. My invention uses fluids for the purpose of lubricating and suspending the spoils, as is colmmon in most oilfield-related drilling, and fluids are not used in any way to steer the product by way of jetting.
A severe drawback of all pre-existing horizontal drilling systems is the inability to drill through rock. Prior to my invention, it was accepted in the industry that most rock formations simply could not be drilled, because the rock is too hard. My system, however, has revolutionized thinking along those lines and has been proven to drill through every type of rock formation, even granite. In addition, my system has operational advantages when used to drill less-challenging formations such as soil or sand.